Androgen can promote the growth of prostate cancer cells. At present, the first choice of treatment for advanced prostate cancer patients is castration treatment including drugs and surgery to reduce the synthesis of androgen by testis, but this treatment cannot inhibit other parts of the body from producing androgen. Abiraterone acetate (Formula II) was marketed in the United States in April and Europe in September, 2011 for the treatment of advanced prostate cancer. Because Abiraterone acetate treatment is an endocrine therapy, which can inhibit testis and other parts of the body from producing androgen, therefore compared with the current conventional treatments, it has a better efficacy, lower side effects, creating a new field of anti-androgen therapy.

Abiraterone acetate exerts its pharmacological effects by convertion to Abiraterone (Formula III) in vivo. Abiraterone is an inhibitor to cytochrome oxidase P450 (CYP450) c17, which reduces the androgen level by inhibiting the key enzyme, CYP450c17, in androgen synthesis. Therefore, Abiraterone not only has inhibition effect androgen produced by testis, but also by other parts of the body such as adrenal gland.

Abiraterone propionate is a homologue of Abiraterone acetate, of which the chemical name is (3β)-17-(3-pyridyl)-androstane-5,16-dien-3-ol propionate, and the structure is represented by Formula I.

WO2014111815A2 discloses Abiraterone propionate. Similar to Abiraterone acetate, Abiraterone propionate can be converted to Abiraterone in vivo and plays its pharmacological effects. At present, there is no report on crystal form of Abiraterone propionate. Therefore, it is important to study the crystal form of Abiraterone propionate.